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Related papers: Twisted mass QCD for the pion electromagnetic form…

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The pion electromagnetic form factor is investigated by using the dispersion relation with the superconvergence condition, which was proposed to synthesize the vector meson dominance model and QCD. The absorptive part is given as an…

High Energy Physics - Phenomenology · Physics 2007-05-23 Keiji Watanabe , Hirohisa Ishikawa , Masami Nakagawa

We present a first Wilson twisted mass fermion calculation of the matrix element between pion states of the twist-2 operator, which is related to the the lowest moment < x > of the valence quark parton distribution function in a pion. Using…

High Energy Physics - Lattice · Physics 2009-11-11 S. Capitani , K. Jansen , M. Papinutto , A. Shindler , C. Urbach , I. Wetzorke

We present the first calculation of the pion electromagnetic form factor at physical light quark masses. This form factor parameterises the deviations from the behaviour of a point-like particle when a photon hits the pion. These deviations…

High Energy Physics - Lattice · Physics 2017-10-23 Jonna Koponen , Francis Bursa , Christine T. H. Davies , Rachel J. Dowdall , G. Peter Lepage

The motivations for simulating QCD thermodynamics with Wilson fermions and a twisted mass term are introduced. The twisted mass approach provides a natural infrared cutoff and O(a) improvement at maximal twist, and can be extended to finite…

High Energy Physics - Lattice · Physics 2008-11-26 E. -M. Ilgenfritz , M. Müller-Preussker , A. Sternbeck , K. Jansen , I. Wetzorke , M. P. Lombardo , O. Philipsen

We present a formula that allows one to calculate the pion form factor in the timelike region 2mpi <= sqrt{s} <= 4mpi in lattice QCD. The form factor quantifies the contribution of two-pion states to the vacuum polarization. It must be…

High Energy Physics - Lattice · Physics 2012-04-04 Harvey B. Meyer

We compute the electromagnetic form factor of the pion using non-perturbatively O(a) improved Wilson fermions. The calculations are done for a wide range of pion masses and lattice spacings. We check for finite size effects by repeating…

We present physics results from simulations of QCD using $N_f = 2$ dynamical Wilson twisted mass fermions at the physical value of the pion mass. These simulations were enabled by the addition of the clover term to the twisted mass quark…

A ratio of lattice correlation functions is identified from which the pion form factor can be obtained directly. Preliminary results from quenched Wilson simulations are presented.

High Energy Physics - Lattice · Physics 2014-11-17 Frederic D. R. Bonnet , Robert G. Edwards , George T. Fleming , Randy Lewis , David G. Richards

This letter is an investigation of the pion form factor utilizing recently developed effective field theory techniques. The primary results reported are: Both the transition and electromagnetic form factors are corrected at order…

High Energy Physics - Phenomenology · Physics 2009-11-10 Ira Z. Rothstein

Results on the electromagnetic form factors of the nucleon using twisted mass fermion configurations are presented. These include a gauge field ensemble simulated with two degenerate light quarks yielding a pion mass of around 130 MeV, as…

We calculate the electromagnetic form factor of the pion in lattice gauge theory. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is used together with the O(a) improved current. The form factor is compared to results…

High Energy Physics - Lattice · Physics 2009-11-10 J. van der Heide , J. H. Koch , E. Laermann , M. Lutterot

We compute the electromagnetic form factor of a "pion" with mass m_pi=330MeV at low values of Q^2\equiv -q^2, where q is the momentum transfer. The computations are performed in a lattice simulation using an ensemble of the RBC/UKQCD…

High Energy Physics - Lattice · Physics 2009-01-06 P. A. Boyle , J. M. Flynn , A. Juttner , C. Kelly , H. Pedroso de Lima , C. M. Maynard , C. T. Sachrajda , J. M. Zanotti

In this contribution, results from $N_f=2$ lattice QCD simulations at one lattice spacing using twisted mass fermions with a clover term at the physical pion mass are presented. The mass splitting between charged and neutral pions…

We test the reweighting of the quark determinant of O(a) improved Wilson fermions in the domain-decomposed hybrid Monte-Carlo algorithm. Specifically, we implement a reweighting in a twisted-mass parameter proposed by Palombi and L\"uscher…

High Energy Physics - Lattice · Physics 2011-11-17 Chuan Miao , Harvey B. Meyer , Hartmut Wittig

We point out a caveat in the proof for automatic O(a) improvement in twisted mass lattice QCD at maximal twist angle. With the definition for the twist angle previously given by Frezzotti and Rossi, automatic O(a) improvement can fail…

High Energy Physics - Lattice · Physics 2009-11-10 Sinya Aoki , Oliver Baer

Lattice QCD with Wilson quarks and a chirally twisted mass term (tmQCD) has been introduced in refs. [1,2]. We here apply Symanzik's improvement programme to this theory and list the counterterms which arise at first order in the lattice…

High Energy Physics - Lattice · Physics 2010-02-03 Roberto Frezzotti , Stefan Sint , Peter Weisz

We present a calculation of the scalar, vector and tensor pion and kaon form factors using one ensemble of two degenerate light, a strange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with clover improvement. The quark…

We present our results on the electromagnetic form factor of pion over a wide range of $Q^2$ using lattice QCD simulations with Wilson-clover valence quarks and HISQ sea quarks. We study the form factor at the physical point with a lattice…

High Energy Physics - Lattice · Physics 2022-01-07 Xiang Gao , Nikhil Karthik , Swagato Mukherjee , Peter Petreczky , Sergey Syritsyn , Yong Zhao

In this paper we calculate the power corrections to the pion transition form factor within the framework of perturbative QCD approach on the basis of $k_T$ factorization. The power suppressed contributions from higher twist pion wave…

High Energy Physics - Phenomenology · Physics 2019-08-07 Yue-Long Shen , Zhi-Tian Zou , Ying Li

Holographic QCD provides a unique framework in which to compute QCD observables. In this talk we summarize recent numerical work on computing the pion electromagnetic form factor using an AdS/QCD action that includes both spontaneous and…

High Energy Physics - Phenomenology · Physics 2017-08-23 Herry J. Kwee , Richard F. Lebed